Safety device



C. W. WYMAN SAFETY/DEVICE,

May 29, 1934.

Filed D60- 17, 1931 UNITED STATES PATENT OFFICE SAFETY DEVICE Charles W. Wyman, Claremont, N. H., assignor to Sullivan Machinery Company, a corporation of Massachusetts Application December 17, 1931, Serial No. 581,709

17 Claims. (Cl. 172-36) This invention relates generally to mining maby causing the gases to pass in a very thin chines of the electric motor propelled type, and stream between suitable relatively cool surfaces, more particularly to the electrical apparatus of the while repeatedly sharply reversing the flow such machines. From another aspect it relates of the stream and subjecting it to eddies.

to drain devices. In the accompanying drawing, in which an The injurious effect of oil upon the insulated illustrative embodiment of the invention is windings of electric motors is well known. In shown, mining machines of ordinary construction, the Fig. 1 is a fragmentary view, inside elevapossibility of damage from such causes is quite tion, with parts broken away, of a mining masubstantial, and in machines in which portions chine constructed in accordance with the illusof the gearing run in oil and which comprise trative form of the invention. motors which are adapted to be tilted or rotated Fig. 2 is a section through the illustrative form in the changing of the plane of cut,-the chance of drain plug. of damage from this source is substantially in- Fig. 3 is a developed view of the parts housed creased. Machines are, moreover, often used in Wit n the il us ativ form of drain p 70 :wet places, and should any water secure access Referring to the drawing, 1 is a mining mato the motor spaces, its discharge would be imchine frame which includes a motor 2 and which .portant. is mounted by means not shown, for rotation The provision of drainage arrangements would about the axis of the motor shaft 3. The motor not be so diflicult were it -not for the fact that comprises a casing 4 within which a rotor 5 75 in many mines explosive gases are present and and field 6 are enclosed. ignition of these gases within the motor spaces The commutating devices of the motor are might be followed by escape ofv the names not shown, being at the right hand end of the through the drainage passages, with resultant motor 2, but it will be evident that should comdanger of great damage to life and property bustible gases secure access to the interior of within the mine. the casing, these might be ignited by a spark A primary object of the invention is to proat the commutator, or if a coil should be burned vide improved means for effecting drainage of ut due to ov rlo r should r u n o c r electric motor casings or other chambers (3011- within the casing 4. At the opposite ends'of 30 taining electrical circuit making and, breaking the casing 4 are frames 7 and 8, each of which apparatus, and combining with efficient drainhouses lubricating mechanism, and lubricant is, age, complete protection against the ignition of despite the best structural Precautions, likely inflammable gases surrounding such chamb to enter the motor casing 4. Moreover, in wet Other objects and advantages of the invention e Water may secure access to the interior will subsequently appear. of the casing 4.

In its general aspect, the invention in l d To drain the casing shown, which is capable im roved eans forming a d in nt d 3550- of being turned over, it is desirable, and indeed i ted means providing f r th effective prg... important, to provide a plurality of drain devices vention of the escape of flame from the space one Of Whch may be at t bottom of the Casing.

40 t b d i ed I preferred f th t and effective, irrespective of the position of the 95 functions may b bi d 1 drain plug motor. Two drains, indicated generally 11 and which houses within it structure forming a t r- 12, are therefore provided, one on the top and tuous passage, prefergbly djviding th gases t the other on the bottom of the casing. As the a thin stream and repeatedly reversing th structure of these drains is alike, but one will direction of flow, for eirtinguishing and cooling be describedany ignited gases which may have occ t As illustrated, each drain device comprises a pass. therethrough, the same passages whi h plug 15, herein shown as threaded at 16 for continguish and cool the gases also serving to drain nection to the casing he plu 15 is travany liquid which may be within the spaces to be ersed y longitudinally extending Passage to drained and protected. Obviously, the cooling 17, nd a h inn n f the p s the p 105 devices need not be contained, however, in a sage s a fl Rt o ac itat detachable plug, but may be disposed in a bore drainage, while the outer end of the passage is in the walls of the motor or controller chamber, expanded to form an enlarged chamber 20. or the like. Advantageously, a screen 21 may be located A peculiarly'eiiective action may be obtained by any suitable means, as a groove 22, into which 110 its edges may be sprung, at or near the mouth of the tapered portion 18 of the passage 17, for the purpose of preventing solid matter of any kind from entering the plug.

Within the chamber 20 are located riameproofing devices, generally designated 25. A wide variety of such devices may obviously be used, the essential features being the restriction of the escape of gases which might become ignited within the motor casing in such manner that they will be cooled and extinguished before reaching the outlet of the drain plug. In order not to defeat the drain function of the plug, however, some structures will be found preferable to others. An arrangement which has proved highly eflective in test includes a number of thin discs 27 each having a segment thereof cut away at 28 to provide a chordal edge 29, these discs being arranged with the chordal edges of each pair of adjacent discs parallel but at opposite sides of the axial line of the discs, and successive discs being spaced by members 30 so narrow radially that a substantial segmental opening 31 remains between the chordal edge 29 of each disc 27 and the inner periphery of the coaxial contacting annuli 30. One suitable material for tbadiscs and annuli, which may be made 'of any substance which will not be injured by exposure to oil and, water and acids such as may be encountered in coal mines, is hard rolled copper; this is suillciently strong and heat resistant to withstand conditions resulting from possible explosions of gases within the motor frame, and is a good heat conductor. Satisfactory annuli and discs both have been made in sizes not over 1 inches in diameter from .0125 inch hard drawn copper stock; and depending upon the number of discs to be used and the cross sectional area of the passages, a substantial variation in the thickness of the stock may be permitted. For a cross sectional area of the passage 17 of inch, I have found good results from the use of twenty-one washers and twenty discs of the thickness mentioned, each having a diameter of 1;; inches and with the inner diameter of the annuli about three-fourths of their outer diameter and the discs 27 cut so that the distances from the center of their edges 29 to the most remote point-in their opposite edges was substantially the same as the inner diameter of the annuli. For smaller passages 17, a smaller number of discs and annuli is satisfactory, and a larger passage would be provided to maintain an equal margin of safety with an increased number.

The discs and annuli may be held in. place by any suitable means, as by clamping between a shoulder 33 at the inner end of the chamber 20 and a shoulder 34 formed by peening over a flange 35 at the outer end of the chamber.

Referring particularly toFigs. 2 and 3, it will be noted that with the discs and annuli most advantageously assembled in a stack in the chamber 20, with a disc intermedate each pair of annuli, there is provided a tortuous passage including segmental portions 36, opening axially of the drain plug andalternately at diametrically opposite sides of the plug, and also including parallel wide, but very shallow, portions 37, in adjacent ones of which fluid flow takes place in opposite directions. The flow area of each segmental portion 36 is, in the illustrative embodiment, many times that of each shallow portion 37. The thinness of the streamof gases which can 'llow throng so construc eu insures cooling and can ishing oi" any burning gases which might start to flow through the plug. The sharp reversals of flow at the portions 36 create eddies which retard flow of gases seeking to rush outward, and also by the eddying, baffling action give rise to a most effective extinguishing action. The use of copper or similar discs provides excellent cooling of the gases and further promotes flame extinguishing action. Obviously, oil and water which may secure access to the interior of the motor casing may flow out through the tortuous passage and maintain the casing constantly drained.

While I have in this application specifically described one form which my invention will assume in practice, it will be understood that this form is shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. A flame-proof drain device comprising means forming a chamber communicable with a space to be drained, and means in said chamber forming a passage providing for drainage by gravity and comprising a plurality of thin superimposed portions of a length and width many times their thickness and in which flow is in opposite directions.

2. A flame-proof drain device comprising means forming a chamber communicable with a space to be drained, and means therein for cooling and extinguishing gases which may flow therethrough and providing for gravity drain age of liquid including means forming a plural ity of substantially parallel thin passage portions communicating with each other to form a bafiled discharge and arranged to prevent entrapping of liquid therein.

3. A flame-proof drain device comprising means forming a chamber communicable with a space to be drained, and means therein for cooling and extinguishing gases which may flow 'therethrough including means forming a plurality of thin, parallel horizontal passage portions communicating with each other to form a passage in whose successive parallel portions flow is in opposite directions.

4. A flame-proof drain device comprising means forming a drain passage, and, between the ends thereof and extending transversely with respect thereto, a stack composed of alternate discs and annuli, said discs having segments cut away to permit flow between the spaces surrounded by successive annuli and being disposed with the cut away portion of each disc adjacent uncut portions of its neighbors.

5. A flame-proof drain device comprising means forming a drain passage, and, between the ends thereof and extending transversely with respect thereto, a stack composed of alternate discs and annuli, said discs having segments cut away to permit flow between the spaces surrounded by successive annuli and being disposed with the cut away portion of each disc diametrically opposite the cut away portions of its neighbors.

6. A flame-proof drain device comprising means forming a drain passage, and, between the ends thereof and extending transversely with respect thereto, a stack composed of thin alternate discs and annuli, said discs having segments cut away to permit flow between the spaces surrounded by successive annuli and being disposed with the cut away portion of each disc adjacent uncut portions of its neighbors.

7. A flame-proof drain device comprising means forming a drain passage, and, between the ends thereof and extending transversely with respect thereto, a stack composed of thin, metallic, alternate discs and annuli of high heat conductivity, said discs having segments cut away to permit flow between the spaces surrounded by successive annuli and being disposed with the cut away portion of each disc diametrically opposite the cut away portions of its neighbors.

8. In combination, a motor casing, and flameprooi' drainage devices therefor arranged at the bottom thereof and providing a drain passage containing sharp reversals in direction.

9. In combination, a casing enclosing electrical apparatus, and drainage devices therefor positioned to preclude rise of liquid level in said casing to a substantial height and providing a relatively wide, thin drain passage containing sharp reversals in direction.

10. In combination, a motor casing disposable in a plurality of positions, and flame-proof drainage devices arranged to drain said casing in a plurality of positions.

11. In combination, a casing containing electrical apparatus, a drain opening from said casing adjacent the .bottom thereof, and means forming a tortuous passage through which drainage must pass in a flattened, frequently reversed stream.

12. A flame-proof drain device comprising means forming an enclosure to provide a drain being disposed with the cut-away portion of .natural flow by gravity of liquid delivered each disc opposite the cut-away portion of the adjacent disc.

13. A flame-proof drain device comprising means forming an enclosure to provide a drain passage, and, between the ends thereof and arranged with its axis extending longitudinally of the drain passage, a stack comprised of alternate discs and annuli, each having plane parallel opposite faces and of a uniform thickness 9. very small percent of their respective diameters, said discs having segments cut away to provide relatively. large eddy chambers and to permit flow between the spaces surrounded by successive annuli' and being disposed with the cut-away portion of each disc opposite the cut-away portion of the adjacent disc.

14. A flame-proof drain device comprising means providing a chamber and baffle and cooling means therein providing a plurality of very thin relatively wide flow passages extending alternately in opposite directions and connecting eddy chambers of many times the flow area oi said flow passages, each eddy chamber communieating directly with and connecting but a single pair of said flow passages.

15. In combination, a motor casing, and flameproof drainage devices therefor having means providing a drain passage containing sharp reversals of direction and providing for alternate downward and horizontal flow exclusively.

16. In combination, a casing providing a chamber enclosing electrical apparatus, and

drainage devices therefor for preventing sub-- stantial trapping of liquid in the chamber, said drainage devices providing a relatively wide, thin drain passage comprising portions providing sharp reversals in direction and connecting relatively straight portions positioned to permit thereto.

17. In combination, a motor casing disposable I with different portions of the surface thereof in lowermost position, and a plurality of flameproof drainage devices respectively arranged to drain said casing in different positions thereof. 1

CHARLES W. WYMAN. 

